1. Field of the Invention
The present invention relates to a pressure control system for use for example, in controlling fluid pressure in the pressure pads of an alternating pressure mattress of a medical bed.
2. Discussion of Related Art
A known pressure control system for an alternating pressure mattress is shown in FIG. 1. The mattress is part of a medical bed and includes two series of inflatable cells which are interleaved, one series within the other. The cells are alternatively inflatable to support a patient at different locations to prevent the formation of decubitus ulcers, known as bed sores.
Typically, inflation and deflation cycles may last from under two minutes to over twenty minutes.
The pressure control system includes a compressor 1 for producing pressurised fluid, typically air, which is coupled to a rotor valve 2 via conduit 3. The rotor valve 2 couples the air to either one or to both of the first and second supply conduits 4 & 5. The conduits 3, 4 & 5 are formed within a manifold which itself is formed from two plate like parts at least one of which includes on an internal surface a recess, the parts being coupled together to provide the conduits.
The manifold also includes a means of connecting directly thereto a fluid source and a pressure control means coupled to the input conduit 3 for controlling fluid pressures in the system. The pressure control includes a single bellows coupled to the input conduit 6 and a discharge conduit 7 able to discharge fluid from the input conduit which operates dependent on the fluid pressure in the bellows. An optional low pressure indicator is also able to be attached to the system which is dependent upon a micro-switch activating when the bellows is inflated or deflated.
Thus the pressure control system has been successful in use. However the pressure control, low pressure indicator and outlets require auxiliary components and tubing to the manifold which can sometimes lead to failures and the tubing provided in the system can be subject to fluid leaks which may be inherent or caused by damage in use.